1. Field
This invention generally relates to mastitis in cows and is most particularly is concerned with a filter device located in the milk line of a milking machine to cause the claw of the milking machine to fall off the cow if the cow has only an early stage case of mastitis or the milk contains impurities from another source.
2. State of the Art
Mastitis is a major problem to the dairy industry costing millions of dollars in loss. Various approaches have been devised to avoid the problem and provide early detection but despite these efforts, the losses caused by mastitis continue. In the past, the use of filters in the milk line of the milking machine has been attempted as a possible solution to the problem. Unfortunately, such efforts have resulted in a solution which is just not workable for an active dairy farm.
In the Bullock et. al. Patent, U.S. Pat. No. 4,376,053, the history of in-line filters is set forth. Based upon that account, in 1969, an in-line clot detector was developed by the National Institute for research in dairying at Reading, England which detector consisted of a stainless steel mesh filter element molded into a 15 mm bore transparent polycarbonate tube at an angle of 45 degrees. The problem with this design is reported to have been quick blocking causing the claws which are placed on the udders of the cows to fall off without detecting mastitis. Obviously, for the cups to fall off upon detecting mastitis would be a benefit and not a detriment. It should be noted that the tube referred to was described as transparent indicating that visual observation of the filter was an essential part of the operation of the device which is not feasible in the operation of a modern dairy farm.
Apparently, prior to the above-described in-line filter, a clamshell type filter was tried but it did not provide good observation of the filter and had hygiene problems. Once again, visual observation was a stated feature of the invention.
The Bullock et al Patent, U.S. Pat. No. 4,376,053, recognized these failings and tried to overcome the problems. Once again, the filter was placed in a transparent container so once again visual observation was clearly a factor in making the invention work. Bullock et. al. wanted to avoid the problem of having the claws fall off the animal during the milking process, when clearly if the claws would fall off only when mastitis was present, there would be no concern with the interruption of the operation. Bullock et. al. taught four designs, but really there were two similar basic concepts with each of the concepts having two variations, one variation being a full wire mesh filter and the other being the same filter with an opening in it. Clearly, Bullock et. al. relied upon visual observation to detect mastitis and preferred to allow the milk of the cow to pass through the filter even if the milk was infected. In a milking barn, with milking occurring twice a day, it would neither be practical nor efficient to monitor all the filters. The invention contemplated by Bullock et. al. would permit detection sooner or later but later would most likely be most common. Certainly, if there was one infected cow, the entire quantity of milk collected would include mastitis infected milk and might be lost. Possibly for this reason, the use of this invention is not commonly known in the current dairy industry which still accepts as inevitable, huge monetary losses from mastitis.
What is needed by the dairy industry is a fail safe device which does require observation but which automatically stops the milking of a cow infected with mastitis even if the cow is only mildly infected but which does not shut down during normal milking operations of a healthy cow. It should also be noted that if mastitis can be detected at an early stage, the infected cow can be cured much more quickly and returned to production. Thus, there is a need not only for sufficiently rapid detection of infected milk without the need visually to monitor the flow so as to avoid contamination of the entire bulk tank supply but also to identify the diseased animal sufficiently early to permit a rapid cure.
The invention as described herein permits fail-safe detection without any need for visual observation but which rather automatically releases and terminates vacuum pressure and causes interruption of the milking process even with a mildly infected cow by causing the claws to drop from the infected animal which was the very concern of the prior art. This is made possible by use of a filter which does not cause the claws to drop when the milk is wholesome. The filter, being readily replaceable and disposable, insures proper hygiene and prompt continuation of the milking process.